Process and apparatus for removing protuberances from metal



July 11, 1933. CAMPBELL, JR 1,917,750

PROCESS AND APPARATUS FOR REMOVING PROTUBERANCES FROM METAL Filed March 1, 1930 9 M E w Q Q W l 4 b I M gwuento'a which such protuberances project.

Patented July 11, I933 UNETEE STTES LORN CAMPBELL, JR.,

PATENT OFFICE OF LAKEWOOD, OHIO Application filed March 1,

This invention relates to a process of and apparatus for the oxidizing and removal of iron or stcel protuberances from bodies of metal without'in'juring the metal bodies from More specifically, the invention relates to a process of and apparatus for the oxidizing and removal of the heads of rivets from the metal plates from which they project, without material oxidation of the metal of such plates.

It is, of course, well known that just so much oxygen is required for the oxidation of so much iron (with allowance for waste).

' This invention, however, provides means for maintaining a high velocity in the oxygen used for preheating while slowing down the velocity of the oxygen employed for oxidizing (or washing) and delivering such oxygen over a much larger area than where used for ordinary cutting, thereby to penetrate to a predetermined depth when, applied to metals heated to the proper temperature and of a nature to permit ready oxidation.

I accomplish the foregoing object in and through a blowpipe such as shown in the drawing hereof, wherein Fig. 1 represents a side elevation of such blowpipe, illustrating the mode of operation; Fig. 2 a longitudinal sectional view through the head and tip of the blowpipe shown in the preceding View; Figs. 3 and 4- are details in section corresponding respectively to the lines 38 and 4-4 of Fig. 2; Fig. 5 is a central longitudinal sectional view through another form of blowpipe tip capable of realizing my invention; and Fig. 6 a detail in section corresponding to the line 6-6 of Fig. 5.

In removing a projection, such as a rivet head, from metal, it has been customary to employ a blowpipe. thereby to first heat the rivet head to the desired temperature, after which the cutting oxygen has been turned on and the rivet head removed. However, great difliculty has been experienced in removing such heads without penetrating the metal plates from which they project, due mainly to the high pressure at which the cutting oxygen is delivered from the blowpipe tips and the difliculty, if not imprac 1930. Serial No. 432,360.

ticability, of reducing such pressure to an extent necessary to enable the desired result to be realized.

- In the practice of my invention, I am enabled to deliver what is termed the highpressure oxygen upon a rivet head under such light pressure and over so large an area of the head as to enable the head to be removed by a gradual oxidizing action which is appropriately referred to as washing the head away. Furthermore, I am enabled to obtain an accurate control of the pressure of the oxidizing or washing gas so applied to rivet heads.

Referring to the drawing, 1 denotes a valve block of standard construction provided with the usual connections for oxygen and a combustible gas, the oxygen connection being indicated at 2. The oxygen is supplied through a passage (not shown) controlled by a valve 3, to the pipe 4, whence it is delivered to a passage 5 in the blowpipe head A. The highpressure or cutting oxygen is supplied by a main, or quick-action, valve having a stem 6 adapted to be engaged by a lever 6 whereby the valve may be unseated when the handle 7 is grasped, thereby to supply high-pressure oxygen from the valve seat through the pipe 8, whence it is delivered through the passage 9 in the blowpipe head, the delivery end of such passage extending upwardly from a chamber 10 projecting upwardly from the bottom of said head.

By means of a valve (not shown) in the block 1, combustible gas is supplied through the pipe 11 and a passage 12 into the chamber 13, below the top thereof.

It will be noted that the chamber13 is cylindrical and provided in its upper part with a thread 10, which is adapted to receive an upper threaded portion 10 on the tip B. The tip is provided at its upper end with a reduced cylindrical extension 12, the upper end of which is rounded, as shown at 12, to engage'the beveled seat 10 in the top of the chamber 10 and surrounding the bottom of the passage 9.

Below the threaded portion 10*, the body of the tip is reduced in diameter, thereby to provide an annular chamber 13 between such by the lever 6*,

reduced portion and the wall of the main chamber 10, the lower end of the passage 12 communicating with such annular chamber.

A leak-proof connection between the tip and the bottom of the chamber 10 is rovided by means of a flanged nut 14 threaded on the lower end of the head, there being a packing ring 15 interposed between the flange of said nut and the lower end of said chamber.

It will be noted that the tip B is provided with a central bore 16, the said bore being shown as of somewhat slightly greater diameter throughout the major portion of its length than the passage 9 and the bore of the pipe 8 through which oxygen is supplied to such bore. At its lower end, the bore is contracted somewhat in diameter, as shown at 16", but outwardly and downwardly divergent ports 17 are provided which communicate with the bottom of the enlarged portion of the bore 16 and deliver part of the oxygen conducted through said bore to the working end of the tip. The aggregate cross sectional areas of the passages 17 and of the lower bore section 16 is approximately equal to the cross sectional area of the bore 16, so that there will be no material obstruction to the free delivery of oxygen to the rivet head or other projection.

Preheating oxygen is delivered through the pipe 4 and passage 5 into the upper end of the chamber 10 and thence through passages 18 extendin to the delivery end of the tip; and combusti le gas is delivered through the passage 12 and chamber 13 into the passages 18 by the short ports 19. The delivery ends of the ports 17 are located adjacent to the delivery ends of the passages 18, six such ports and passages being shown.

It will be noted further that, in addition to the ordinary high pressure valve, opened I employ an auxiliary valve 20, preferably applied to the pipe 8, the valve being of the ordinary needle-valve type. By interposing this valve in or between the high pressure valve, and the tip, I interpose an adjustable restriction in the oxygenpassage between the ordinary valve and the tip which will provide between such restriction and the delivery end of the tip a passage of suflicient length to enable me to reduce to an extent necessary for successful operation the velocity and pressure of the oxygen delivered through the tip, thereby to completely oxidize or wash the rivet or bolt-head after it has been heated to the desired temperature by the preheating jets delivered through the passa es 18.

Re erence has been made hereinbefore .to the arrangement of the bores 0r passages 17. This arrangement results in such a spreading of the oxygen delivered through the bores 16" and 17 as to secure a most eflicient washing or oxidizing of the rivet head without penetration of the metal of the plate from which it projects.

One of the great advantages of interposing the valve 20 between the main high-pressure oxygen valve and the blowpipe tip is that it enables beyond the auxiliary valve to be adjusted as desired for different sized rivets or work, after which the oxygen used for washing or oxidizing purposes will be retained at such pressure. p

In Figs. 5 and 6, a ti B is shown wherein the bore 16 extends wit out restriction or variation in cross sectional area throughout the entire length of the tip. In this case, all of the oxygen for oxidizing or washing the rivet heads or projections I is delivered through a single bore which is of proper size to produce correct volume and velocity of such oxygen.

In the practice of my invention, a rivet head, such as indicated at C is preheated by the jets delivered through the passages 18 in the usual manner, the axis of the bore 16 substantially coinciding with the axis of the shank of the rivet C, as shown in Fig. 1. This enables the preheating jets to operate entirely within the periphery of the rivet head. When preheated to the desired extent, the main high pressure oxygen valve is opened in the usual manner by the lever 6 and the valve 20 adjusted so as to obtain the desired volume and low velocity in the gas delivered through the passages or bores 16, 16 and 17. of the tip. When this valve is properly adjusted, the rivet head will be oxidized without penetration of the cutting or oxidizing action into the metal D surrounding the rivet hole, leaving an annulus C of the head, severed from the body of the shank or the rivet, after which the shank, together with the opposite head of the rivet, may be easily driven out.

Having thus described my invention, what I claim is:

The process of oxidizing an iron or steel projection extending from a metal plate which consists in first heating the said projection to the desired temperature, and then subjecting the projection to the action of a jet of oxygen delivered upon the central portion thereof and at substantially right angles to the plane of said plate and to the action of a plurality of jets of oxygen arranged radially outside such central jet and delivered upon the said projection within the periphery thereof, the oxygen being delivered under low pressure through such jets.

In testimony whereof, I hereunto afiix my signature.

LORN CAMPBELL, JR. I

the pressure of the oxygen- 

